CANADA. 



357 



marvellous instances on record of * selective metamoriMsm, But whether this 

 is so or not, there seem to be no good grounds for assigning either an age or an 

 origin to the cupriferous diorites, dolerites, and aniygdaloids of the Eastern 

 Townships different from that of the almost identical rocks of Lake Superior." 



Of the Hastings scries he says : 



" The gradual progress of the work, however, from west to east has now, I 

 think, conclusively demonstrated that the Hastings group, together with the 

 somewhat more crystalline limestone and gneiss groups, .... form one great 

 conl'orniable series, and that this series rests (pite nnconformably on a massive 

 granitoid gneiss." 



Of the Norian rocks he said : 



" In not one of the several areas where they are known to occur in Canada, 

 have they yet been mapped in detail, and even their limits, as indicated on the 



geological map, are more or less conjectural Professor Iliichcock shews 



that they rest nnconformably on the upturned edges of the ' Montalhan ' gneisses, 

 leading to the conclusion that the gneisses of the White Mountains are older 

 than the ' Norian/ whereas Dr. Hunt, solely, I believe, on nuueralogical con- 

 siderations, supposes these same ' MontalhaiV g\\Q,k^<i^ to constitute a system 

 newer than the Huronian. iiere, then, as in the Hastings region, we find 



theory and experience at variance If it is admitted — whicli, in view 



of the usual associations of Labrador feldsjxxrs, is the most probable supposi- 

 tion — that these anorthosite rocks represent the volcanic and intrusive rocks 

 of the Laurentian period, tiien also their often massive and irregular, and 

 sometimes bedded character, and their occasionally interrupting and cutting 

 oir some of the limestone bands, as described by Sir W. 111. Loga.n, is readily 

 understood by one who has studied tlie stratigraphical relations of contempo- 

 raneous volcanic and sedimentary st]'ata, of palaio/.oic, mesozoic, tertiary and 

 recent periods. Chemical and microscopical investigation both seem to point 

 very closely to this as the true explanation of their origin. That they are 

 eruptive roclcs is held by nearly all geologists Avho h;i,ve carefully studied 



their stratigraphical relations When we recall the names of Dahl, 



Kerulf and Torrell in Norway, MacuUoch and Geike in S(^otlan(l, Emmons, 

 Kerr, Ilitt^hcock, Arnold Hague, and others in America, all of whom consider 

 these norites as of eruptive origin, we may well pause before accepting Dr. 

 Hunt's conclusions respecting them, and that they shouLl often appear as 

 ^ bedded metamorphic rocks,' .... is quite as prftbable as that we should 

 find the niiiicralogically similar dolerites occuring in dykes and bosses, and in 

 vast beds interstratified with ordinary sedimentary de[>osits of clay, sand, etc., 

 as we do over wide areas in Australia and elsewhere. In conclusion, I may 

 say that I fail to see that any useful purpose is accomplished, in the present 

 stage of our knoAvledge of the stratigra,phical reliitions of the great groups of 

 rocks Avhich underlie the lowest known Silurian or Cambrian formations, by 

 the introduction of a number of new names such as those proposed by Dr. 



